Nanotechnology最新文献

All-inorganic metal halide perovskite materials exhibit high photoluminescence quantum yields (PLQYs), broad emission bands, and tunable luminescence-attributes that confer great potential for white light applications. However, reports on Cd-based perovskites for efficient white light emission remain scarce. Here, the hydrothermal synthesis of Pb²⁺/Mn²⁺co-doped Rb₃Cd₂Cl₇ perovskite crystals, in which the substitutions of Cd²⁺by Pb²⁺or Mn²⁺form the luminescent centers of [PbCl₆]⁴^-and [MnCl₆]⁴^-for white emission, is reported. Doping with Pb²⁺enables a deep-blue emission at 443 nm with anti-thermal quenching and a maximum PLQY of 58.58%, attributed to the formation of confined exciton around [PbCl₆]⁴^-. Concurrently, Mn²⁺ion doping induces energy transfer toward intrinsic self-trapped exciton (STE) states to [MnCl₆]⁴^-, yielding intense yellow emission at 588 nm with a maximum PLQY of 137.79%. This emission is attributed to the intrinsic Cd-related STEs, combined with the generation of local exciton magnetic polarons (LEMPs) through ferromagnetic (FM) Mn²⁺-Mn²⁺interactions, via assistance of the coupling with the 245.3 cm^-1phonon mode in Rb₃Cd₂Cl₇: Mn²⁺. The co-emission of^PbCE and LEMP, from the interaction of Pb²⁺and Mn²⁺centers, achieved a PLQY of 75.4% for white light emission. The white light-emitting diodes exhibit an excellent color rendering index of 94.1, which is exceptional among recent devices compared to those based on Cd. This underscores its potential for significant applications in the optoelectronic field and offers a new alternative material for perovskite blue and white LEDs.

This paper presents a wafer-scale NiO (a prototype Mott material)/ferroelectric heterostructure termed as ferroelectric Mott (FeMott), which is capable of room-temperature operations as a gate tunable electrical switch, in deep contrast with several existing Mott transistors that operate at around 70°C and are based on VO₂, which is the most widely used Mott material. Here, FeMott devices made using NiO illustrate a reversible insulator-metal transition (IMT), which was first investigated by Mott and referred as the first known Mott material. We show that integrating NiO with an yttrium-doped HfO₂(HfYO) ferroelectric layer enables electrical switching through an electrically induced IMT. This switching mechanism is attributed to the electronic interactions between NiO and HfYO, which possess a significant remanent polarization of 80μC cm^-2and a coercive electric field of 2.7 MV cm^-1at room temperature. The device exhibits a gate voltage control of the IMT starting at 1μV, resulting in a high ON/OFF ratio of five orders of magnitude.

Graphene is one of the most important carbon materials in the global trend of nanotechnology application and sustainable development. Beside liquid-phase exfoliation, solid-phase exfoliation, chemical vapour deposition and electrochemical methods, the most popular technology for large-scale production of graphene-based nanosheets is the chemical route of oxidation-reduction reactions. Chemical conversion of natural/artificial graphite into graphite oxide (GrO) requires a strong oxidation reaction, typically using manganese (VII) oxidant in improved Hummers methods, to generate numerous oxygen-containing functional groups on graphene planes in multilayer graphite structure. Ultrasonic exfoliation of hydrated multilayer GrO in water produces an aqueous dispersion of graphene oxide nanosheets (GO) for next reduction reaction, restoring conductiveπ-conjugated graphene domains in reduced GO (RGO). While green reducing agents like vitamin C and sugars are eco-friendly choices, highly alkaline solutions emerge as an efficient approach to synthesizing non-stacked RGO. Among strategies for preventing graphene restacking through hydrophobic force andπ-πinteraction, bioinspired supramolecular graphene-based materials are excellent to preserve and produce solution-processable nanostructures for a variety of applications. In this review, advancements in chemical oxidation and reduction reactions for synthesizing GO and RGO are highlighted, particularly mechanism of cascade design oxidation process using manganese (VII) oxidant, mechanism of GO reduction reaction using highly alkaline solutions, and the reversible self-assembly of graphene-based materials. Moreover, the review summarizes the conceptualization, density functional theory calculation and experimental syntheses of supramolecular hydration structures of graphene-based hydrogels, including multifunctional applications in aqueous dispersions, water purification, photocatalysis, biosensing, antibacterial hydrogels, polymer nanocomposites, nanostructured coatings and energy devices.

As nanoscale luminescent semiconductors with wide-range access to many precursors, carbon dots (CDs) represent an extremely biofriendly structure with easy and low-cost preparation methods. In the meantime, antibiotic resistance is a global challenge that needs utmost attention for health. In the current study, luminescent CDs were prepared using the solvothermal treatment ofcitrus tangerinepeel-extract. With a bluish excitation-dependent emission, the amorphous CDs include C, O, Ca, and K elements. Biomass-based CDs showed reliable antimicrobial activity against various gram-positive and -negative bacteria. The antibacterial effects of CDs were evaluated and compared with some antibiotics that are routinely used for treatment of infection caused by these bacteria. Our results showed that the antibacterial effects of CDs were more effective than amikacin, gentamycin and ceftazidime in most of the bacterial cultures. It revealed somehow identical properties to that of imipenem, while a little bit worse bactericidal activity compared to ciprofloxacin and cefixime was obtained. In conclusion, the prepared CDs can be an effective alternative for antibiotics, although their side effects in the body have to be investigated.

In recent decades, significant progress has been made in the development of quantum dots (QDs) as sensing materials in advanced sensor technology. This review discusses the brief history, significance, and advancements of QD-based gas sensors. Additionally, it emphasizes the integration of artificial intelligence (AI) and nanotechnology to enhance sensing performance. These advancements have resulted in improved selectivity, sensitivity, and overall performance. However, challenges such as reproducibility and environmental stability persist, requiring further investigation. Emerging innovations are actively addressing these limitations that aims for the wider implementation of QD-based gas sensors. Given their transformative potential, these materials could play a crucial role in industrial safety, medical diagnostics, and environmental monitoring.

Extracellular vesicles (EVs) are membrane bound nanoscale particles released by cells that contain molecular cargo reflective of their parental cell and can be found in many biofluids. The overexpression of EVs and EV-related protein markers has been linked to various diseased states, making them a promising tool for liquid biopsy-based disease diagnostics. Many complex diseases, like cancer, impact multiple markers simultaneously, and during early stages, are present at low concentrations. Current EV analysis technology is limited in sensitivity, multiplexing, and ease of use. We have developed a silver nanoparticle embedded membrane (sNEM) platform that utilizes the 3D structure of nitrocellulose membrane, metal-enhanced fluorescence (MEF)-based detection and a novel wax-based compartmentalization technique for highly sensitive multiplex EV protein detection from minimal sample volume. We compared various nanoparticle shapes, sizes, and metal types with fluorophores of different wavelengths to determine which provided optimal MEF-based detection with high sensitivity. Fluorescence intensity from FITC was much lower than that from Cy5 and was found to pronounce the effects of autofluorescence by 2 times. After selecting 30 nm silver nanoparticles at a concentration of 10⁹particles ml^-1and the Cy5 fluorophore based on greatest fluorescence enhancement, we then demonstrated its application for multiplexed detection of surface and intravesicular proteins directly from lysed EVs in both buffer and human plasma. In PBS, detection limits of 2-3 orders of magnitude lower than traditional ELISA were achieved. Directly from human plasma, detection limits of 1.97 × 10⁵EVs ml^-1, 1.94 × 10⁶EVs ml^-1, and 2.17 × 10⁴EVs ml^-1for TGF-β1, AKT1, and TSG101 were achieved. These results demonstrate the suitability of sNEM for highly sensitive, multiplexed detection of EV markers from complex biofluids for early diagnostics while offering advantages such as low reagent/sample consumption, scalability, reduced sample preparation, and ease of use.

Leishmaniasis, a vector-borne disease transmitted by phlebotomine sandflies and caused by protozoa of the genus Leishmania, constitutes a significant public health challenge, with approximately one million new cases reported annually. Current therapeutic options are constrained by issues related to toxicity, suboptimal efficacy, and elevated costs. This study details the formulation, lyophilization, physicochemical characterization, and in vitro assessment of poly(lactic acid) (PLA) nanoparticles encapsulating SB-83, a novel antileishmanial compound, with the aim of enhancing its therapeutic profile. The nanoparticles were prepared via the nanoprecipitation method, yielding spherical particles with mean diameters ranging from 146,4 to 239 nm. The lyophilization process was capable to obtain NPs with excellent stability and particle recovery and shows influence in SB-83 delivery. Encapsulation efficiency varied between 65% and 86%, contingent upon the specific preparation method. A sustained release of SB-83 from the nanoparticles was observed over a period of up to 96 hours. In vitro analyses confirmed the efficacy of SB-83-loaded nanoparticles against both promastigote and amastigote forms of Leishmania (L.) amazonensis, demonstrating a substantial increase in the selectivity index to 50% and a reduction in cytotoxicity toward macrophages by more than 85%. Collectively, these findings indicate that PLA nanoparticles loaded with SB-83 offer a promising drug delivery platform for the treatment of leishmaniasis, providing prolonged release, enhanced efficacy and selectivity against the parasite, and decreased adverse effects. These results underscore the potential of nanoparticle-based systems as innovative and effective therapeutic strategies for leishmaniasis.

Colon cancer is one of the leading cancers worldwide, with standard treatments hindered by inadequate targeting and toxicities that limit dosage. Nanotechnology offers a revolutionary framework for targeted drug delivery, utilizing nanoscale effects to improve treatment accuracy. This examination focuses on chitosan nanoparticles (CNPs) as innovative nanocarriers, leveraging their unique nanoscale features like sizes between 50-300 nm, elevated surface-to-volume ratios, and positive zeta potentials (+20 to +50 mV) to facilitate mucoadhesive interactions and improved passage through biological barriers. We emphasize novel synthesis methods, such as ionic gelation utilizing tripolyphosphate for creating particles under 100 nm and eco-friendly techniques with plant extracts for sustainable scalability, enabling accurate regulation of polydispersity indices (<0.2) and drug encapsulation efficiencies (>80%). Functionalization of surfaces with ligands (such as folate or hyaluronic acid) promotes receptor-mediated endocytosis, leveraging quantum confinement-like effects in surface charge distribution to enhance cellular uptake in colon cancer receptors that are overexpressed. Preclinical findings demonstrate stimulus-responsive actions, including pH-activated disassembly in the acidic tumour milieu (pH 5.5-6.5) or enzyme-facilitated release by colonic glycosidases, resulting in prolonged drug payloads (like 5-fluorouracil or curcumin) with 2-5 times greater bioavailability and minimized off-target impacts. Incorporating magnetic or fluorescent elements allows for multifunctional theranostics that merge nanoscale imaging with therapeutic applications. Despite challenges in mass production and in vivo stability, continuous progress in nanoscale enhancements is set to close preclinical gaps, establishing CNPs as a fundamental element for future colon cancer treatments through quantum-inspired precision and biocompatibility.

Chiral optical metasurfaces have emerged as a promising platform in coupling with molecular vibrational fingerprints through the enhanced light-matter interaction under different circularly polarized light illumination. This work reports the mode coupling between the mid-infrared phonon vibrations of polymethyl methacrylate (PMMA) molecules and the thermally tunable chiral metasurfaces based on the phase-change material Ge₂Sb₂Te₅ (GST-225). Phase-change chiral metasurfaces with high circular dichroism (CD) in absorption and tunable plasmonic resonance in the frequency range of 48-56 THz are demonstrated, which covers the phonon vibrational frequency of PMMA molecules at 52 THz. The mode splitting features are observed in the absorption and CD spectra when the metasurface resonance is tuned across the phonon vibrational frequency of PMMA molecules during the phase transition of GST-225. The underlying mechanism of molecule-metasurface coupling is further revealed by studying the electric field and power loss density distributions of the phonon-plasmon coupled modes under both left-handed and right-handed circularly polarized (LCP and RCP) light. The demonstrated results show the potential of dynamically tunable chiral metasurfaces for the applications in label-free molecular sensing, biomedical diagnostics, thermal imaging, and mid-infrared photonics.

Heat transfer from a liquid-vapor phase change is widely used in industry for thermal management. Improving the heat transfer efficiency of the phase change could yield substantial energy savings and reduce greenhouse emissions. In this work, the heat transfer performance of a nanoporous Teflon surface was tested using droplet vaporization experiments with acetone as the working fluid. The nanoporous surface was heated to various temperatures and the vaporization process was recorded using a digital camera at a high motion frame rate of 60 fps. The time required to vaporize a given volume of acetone and the area of the droplet on the surface were used to calculate the heat flux. The nanoporous surface demonstrated 1.8× enhanced heat transfer and 2.8× faster vaporization rates than a flat Teflon surface for the same liquid volume.